This invention relates to a system for panning apparent audio sound relative to a listening area through automatic controls. More particularly, the present invention relates to control systems for audio reproduction wherein the apparent source of one or more sounds can be panned relative to the listening area.
Various prior efforts have been directed toward producing apparent sound sources which move relative to a plurality of speakers as perceived by a listener. The classic two-channel stereo systems provide this effect by recording from multiple receiving devices into the two channels which then produce sound movement effects through the reproduction of those two channels at a plurality of transducers. Such systems are effectively restricted to sound reproduction of the actual recordings and generally utilized only for apparent sound movement relative to two output speakers.
More recently, efforts have been directed towards obtaining sound which appears to come from any direction relative to a listener in so-called quadraphonic effects by situating three or more speakers around the listening area. One of these means for controlling the quadraphonic reproduction is through a four-way joystick control by the operator. Yet another is to cyclically connect the audio sources to the various speakers so that the sound appears to continuously rotate around the listening area, one such system being shown in U.S. Pat. No. 3,374,315 by Gladwin. Yet another system which causes sound rotation between speakers is shown in U.S. Pat. No. 3,568,783 by Brickner wherein a low frequency audio spectrum is subsonically rotated between low frequency speakers to enhance the stereo effect of the system. An arrangement intended to improve the distance and reverberation effects for sound movement is shown in U.S. Pat. No. 3,665,105 by Chowning.
Although the prior art systems have improved the stereophonic quality of sound reproduction and have further enhanced the quadraphonic effects, the prior art does not permit the operator to readily select from prestored quadraphonic effects nor does it provide an arrangement wherein multiple sound sources can appear to follow preselected apparent sound patterns under operator or automatic controls.